Citric Acid Cycle and Cellular Respiration

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Where does the process of glycolysis occur?

Cytoplasm (correct)

Endoplasmic reticulum

Mitochondria

Nucleus

What happens to the carbon atoms during glycolysis?

They are converted into ATP

They are stored in the mitochondria

They are split into two molecules of pyruvate (correct)

They are released as carbon dioxide

What is the energy yield of glycolysis?

36 ATP

4 ATP

0 ATP

2 ATP (correct)

What is the purpose of the energy-investment phase of glycolysis?

To invest energy in the form of ATP to facilitate the breakdown of glucose Signup and view all the answers

How is glycolysis regulated?

By feedback inhibition Signup and view all the answers

What is the result of high levels of ATP binding to the regulatory site of phosphofructokinase?

The enzyme is inhibited Signup and view all the answers

What is the condition required for re-oxidation of FADH2?

Aerobic conditions Signup and view all the answers

What is the significance of the fourth step of glycolysis?

It divides the glucose molecule into two pieces Signup and view all the answers

Which stage of cellular respiration can function anaerobically?

Glycolysis Signup and view all the answers

What is the role of CoA in the citric acid cycle?

To drive an oxidation and a reduction step forward Signup and view all the answers

Why is it necessary for ATP to bind to the active site of phosphofructokinase?

To activate the enzyme Signup and view all the answers

What is the net production of ATP per glucose molecule in the reactions so far?

2 ATP Signup and view all the answers

Where is most of the energy stored at this point?

NADH and FADH2 Signup and view all the answers

Where is the electron transport chain located in the mitochondrion?

Inner mitochondrial membrane Signup and view all the answers

What happens to the electrons as they pass through the electron transport chain?

They decrease in free energy Signup and view all the answers

What is the result of electron transfer in the electron transport chain?

Protons are pumped into the intermembrane space Signup and view all the answers

What is the net ATP yield of glycolysis?

2 ATP Signup and view all the answers

What is required to keep glycolysis running?

Glucose Signup and view all the answers

In anaerobic respiration, what is the terminal electron acceptor?

Sulfate Signup and view all the answers

What is the primary mechanism of ATP production in fermentation?

Substrate-level phosphorylation Signup and view all the answers

What is the flow of energy during cellular respiration?

Glycolysis → Electron transport chain → ATP synthesis Signup and view all the answers

What is the purpose of the proton-motive force in the electron transport chain?

To generate ATP Signup and view all the answers

What is the role of ATP synthase in the electron transport chain?

To use the proton-motive force to drive ATP synthesis Signup and view all the answers

What is the process by which energy from a proton-motive force is used to drive ATP synthesis?

Chemiosmosis Signup and view all the answers

Study Notes

Cellular Respiration

In the absence of oxygen, NADH can be re-oxidized, but FADH2 can only be re-oxidized when oxygen is available.
Glycolysis is the only stage of cellular respiration that can function anaerobically.
CoA is used in two steps of the citric acid cycle, acting as an agent to drive the reactions forward.

Oxidative Phosphorylation: Electron Transport Chain and Chemiosmosis

Electrons are transferred from NADH or FADH2 to the electron transport chain.
The electron transport chain is located in the inner mitochondrial membrane.
Electrons are passed through a series of proteins to oxygen, ultimately forming H2O.
The electron transport chain generates no ATP, but breaks the large free-energy drop from food to O2 into smaller steps.
Electron transfer in the electron transport chain causes proteins to pump H+ ions from the mitochondrial matrix to the intermembrane space, creating a proton-motive force.
The energy stored in the H+ gradient is used to drive ATP synthesis through chemiosmosis.
ATP synthase uses the exergonic flow of H+ ions to drive ATP synthesis.

Chemiosmosis

Chemiosmosis is the use of energy in a H+ gradient to drive cellular work.
In oxidative phosphorylation, the energy from the electron transport chain is used to pump H+ ions across the membrane, creating a proton-motive force.
This force is then used to drive ATP synthesis through ATP synthase.

Fermentation and Anaerobic Respiration

Glycolysis can produce ATP with or without oxygen, but most cellular respiration requires oxygen to produce ATP.
In the absence of oxygen, glycolysis couples with fermentation or anaerobic respiration to produce ATP.
Anaerobic respiration uses an electron transport chain with an acceptor other than O2, such as sulfate.
Fermentation uses substrate-level phosphorylation to generate ATP.

Citric Acid Cycle and Oxidative Phosphorylation

The citric acid cycle completes the breakdown of glucose.
Oxidative phosphorylation accounts for most of the ATP synthesis.

Glycolysis

Glycolysis breaks down glucose into two molecules of pyruvate.
Glycolysis occurs in the cytoplasm and has three major phases: energy-investment, cleavage, and energy-payoff.
Two ATP are used at the beginning of glycolysis to phosphorylate the glucose.
Glycolysis is regulated by feedback inhibition.
High levels of ATP inhibit the third enzyme, phosphofructokinase.
Phosphofructokinase has two binding sites for ATP: one active site and one regulatory site.
The fourth step of glycolysis is the aldolase step, where the molecule is broken into two pieces.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Understanding the citric acid cycle and its relation to cellular respiration, including the roles of NADH, FADH2, and CoA. Quiz covers the stages of cellular respiration and the conditions required for certain reactions to occur.